The axial size of such machines is a determining factor for the cost of installing elevators.
U.S. Pat. No. 4,960,186 discloses a machine in which a pulley is fixed on an end wall of the rotor, thus making it possible to use a pulley of a diameter that is smaller than the diameter of the rotor.
Machines having a disk-shaped rotor and a reduced axial size have been proposed, for example in U.S. Pat. No. 5,996,742.
U.S. Pat. No. 4,771,197 discloses a machine in which the grooves of a pulley are made around the rotor. European Patent EP 0,706,968 and German Patent DE 199 03 409 describe other machines.